A jury finds James Arthur Ray guilty of negligent homicide in the 2009 deaths of three clients. One victim's family plans a watchdog group to monitor the self-help industry.

A jury in Arizona convicted a bestselling author and self-help guru Wednesday in the deaths of three clients during a sweat lodge ceremony in 2009 that was intended to help participants overcome adversity to reach their full potential.

After hearing four months of testimony, the eight-man, four-woman jury deliberated for fewer than 12 hours before finding James Arthur Ray guilty of three counts of negligent homicide.

The panel acquitted Ray of the more serious charges of manslaughter.

Wearing a dark jacket and dress shirt in the Camp Verde courtroom, Ray sat silently during the televised proceedings, his face breaking into relief when the manslaughter charges were rejected. He became grimmer when the clerk announced that the jury had convicted him of the lesser charges.

Prosecutors argued that Ray was criminally negligent in subjecting Kirby Brown, Liz Neuman and James Shore to life-threatening conditions, and that he deserved prison for their deaths. They played a recording of him urging participants to ignore their bodies' signs of distress during what he called a "hellacious" event.

Ray's attorneys argued that the 56 participants, who paid $10,000 each to attend the five-day "Spiritual Warrior" session, had signed waivers acknowledging that they understood death was a risk. They also argued that the state had botched the investigation, and that toxic substances outside, such as rat poison, could have contributed to the deaths.

Ray faced up to 37 years in prison if convicted of the manslaughter charges. He faces up to 11 years on the three negligent homicide convictions but could be sentenced to nothing more than probation. The mitigation phase of his trial begins next week, with testimony on whether he deserves prison for his crimes. No date has been set for sentencing.

Ray left the courthouse without commenting. Families of the deceased expressed relief.

Before the disastrous ceremony outside the New Age playground of Sedona, Ray had been on a rapid ascent in the rarefied, $11-billion industry of self-help gurus. Thousands attended the free lectures he gave around the country, and many of them later ponied up thousands of dollars to enroll in one of his many workshops.

Propelled by an appearance in a 2006 documentary called "The Secret," about rules for success, he had appeared on "The Oprah Winfrey Show" and "Larry King Live." His business, based in Carlsbad, Calif., brought in $10 million annually and was growing fast, according to Inc. magazine.

During the trial, witnesses testified about the chaotic, two-hour event in the steam-filled sweat lodge. It ended with dozens of clients being dragged from the building. In addition to the deaths, more than 20 people were hospitalized.

As authorities investigated his role in the deaths, Ray ended his seminars but continued to give motivational talks. Yavapai County Superior Court Judge Warren Darrow denied a motion by prosecutors to have Ray immediately taken into custody after his conviction. He remains free on a $525,000 bond.

The family of Kirby Brown announced Wednesday that they would start a nonprofit group to try to police the self-help industry. "As the horrific details of the three deaths emerged in this trial, we realized that the potential danger posed by 'self-help' gurus extends well beyond James Ray," the family said in a statement.

Thomas McFeeley, Brown's cousin, said in an interview that the family took no pleasure in the verdict but hoped it would ensure that Ray "never does this again to anyone else."

"Prison," McFeeley said, "might be the best place for him to do that."